Influence of aluminum sol with different pH on performance of shaped mordenite catalyst for dimethyl ether carbonylation
The production of dimethyl ether(DME)from syngas,followed by the carbonylation of DME to produce methyl acetate(MA),and the hydrogenation of MA to ethanol is a green process route with high conversion and selectivity,mild reaction conditions,and low separation energy consumption.Among them,the dimethyl ether carbonylation reaction,as an important intermediate reaction,has attracted great attention from scholars.The present work focuses on the reaction of carbonylation of DME to MA,using mordenite(MOR)with high carbonylation activity and stability to prepare shaped catalysts,which lays a foundation for further industrialization.A series of extruded MOR catalysts were prepared by using aluminum sol with different pH as binder and compared with shaped catalysts using pseudo-boehmite as binder.The effect of the binder on the strength of the shaped catalysts was investigated by strength tests as well as statistical analysis of the Weibull function.The role of the binder on the physical structure,acidity and catalytic performance of the MOR was investigated by characterization such as X-ray diffraction,N2 physical adsorption,29Si MAS NMR,and in-situ pyridine adsorption infrared in combination with the evaluation of catalytic properties.The results showed that the pH of the aluminum sol had a very important effect on the pore structure,mechanical properties and catalytic performance of the shaped catalyst.When the pH of the aluminum sol is 4.9,the extruded catalyst had the largest mesoporous specific surface area and volume(70 m2/g and 0.20 cm3/g),the highest mechanical strength(110.7 N/cm)and the smallest decrease in the amount of Brønsted acid by unit mass of zeolite.Therefore,the extruded catalyst had the highest DME conversion and space-time yield by unit mass of zeolite.
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